Hypothetically, yes. Anything is possible.
Realistically, I've seen threads on SDN where the answer always seems to be no. Dental schools are assembling classes for next fall. Deferred entrance seems to only be with compelling circumstances.
I wouldn't recommend calling the dental schools on this one. You could always start, have an emotional crisis a week later, ask to start over next year, and use your student loans to go live the good life (a generalized term) for a year.